Protected Conversion Solar Power System

ABSTRACT

Different systems to achieve solar power conversion are provided in at least three different general aspects, with circuitry that can be used to harvest maximum power from a solar source or strings of panels for DC or AC use, perhaps for transfer to a power grid three aspects can exist perhaps independently and relate to: 1) electrical power conversion in a multimodal manner, 2) alternating between differing processes such as by an alternative mode photovoltaic power converter functionality control, and 3) systems that can achieve efficiencies in conversion that are extraordinarily high compared to traditional through substantially power isomorphic photovoltaic DC-DC power conversion capability that can achieve 99.2% efficiency or even only wire transmission losses. Switchmode impedance conversion circuits may have pairs of photovoltaic power series switch elements and pairs of photovoltaic power shunt switch elements.

This application is a continuation of U.S. patent application Ser. No.13/934,102, filed Jul. 2, 2013, which is a continuation of U.S.application Ser. No. 13/275,147, filed Oct. 17, 2011, which is acontinuation of U.S. application Ser. No. 13/192,329, filed Jul. 27,2011, now U.S. Pat. No. 8,304,932, issued Nov. 6, 2012, which is acontinuation of U.S. application Ser. No. 12/955,704, filed Nov. 29,2010, now U.S. Pat. No. 8,004,116, issued Aug. 23, 2011, which is acontinuation of U.S. application Ser. No. 12/682,889, filed Apr. 13,2010, now U.S. Pat. No. 7,843,085, issued Nov. 30, 2010, which is theUnited States National Stage of International Application No.PCT/US2008/057105, filed Mar. 14, 2008, which claims benefit of andpriority to U.S. Provisional Application No. 60/980,157, filed Oct. 15,2007, U.S. Provisional Application No. 60/982,053, filed Oct. 23, 2007,and U.S. Provisional Application No. 60/986,979, filed Nov. 9, 2007,each said patent application and any priority case hereby incorporatedherein by reference.

TECHNICAL FIELD

This invention relates to the technical field of solar power,specifically, methods and apparatus for converting electrical power fromsome type of solar energy source to make it available for use in avariety of applications. Through perhaps three different aspects, theinvention provides techniques and circuitry that can be used to harvestmaximum power from a solar cell, a solar panel, or strings of panels sothat this power can be provided for DC or AC use, perhaps for transferto a power grid or the like. These three aspects can exist perhapsindependently and relate to: 1) providing electrical power conversion ina multimodal manner, 2) establishing a system that can alternate betweendiffering processes, and 3) systems that can achieve efficiencies inconversion that are extraordinarily high compared to traditionalsystems.

BACKGROUND

Solar power is one of the more desirable types of renewal energy. Foryears it has been touted as one of the most promising for ourincreasingly industrialized society. Even though the amount of solarpower theoretically available far exceeds most, if not all, other energysources (renewable or not), there remain practical challenges toutilizing this energy. In general, solar power remains subject to anumber of limitations that have kept it from fulfilling the promise itholds. In one regard, it has been a challenge to implement in a mannerthat provides adequate electrical output as compared to its cost. Thepresent invention addresses an important aspect of this in a manner thatsignificantly increases the ability to cost-effectively permit solarpower to be electrically harnessed so that it may be a cost-effectivesource of electrical power.

One of the most efficient ways to convert solar power into electricalenergy is through the use of solar cells. These devices create aphotovoltaic DC current through the photovoltaic effect. Often thesesolar cells are linked together electrically to make a combination ofcells into a solar panel or a PV (photovoltaic) panel. PV panels areoften connected in series to provide high voltage at a reasonablecurrent. This may be accomplished to make electrical interconnect losseslow. The output of a solar cell or a solar panel, or even combinationsthereof, is frequently then converted to make the electrical power mostusable since the power converters often employed can use high voltageinput more effectively. Conventional power converters sometimes evenhave at their input handled by an MPPT (maximum power point tracking)circuit to extract the maximum amount of power from one or more or evena string of series connected panels. One problem that arises with thisapproach, though, is that often the PV panels act as current sources andwhen combined in a series string, the lowest power panel can limit thecurrent through every other panel.

Furthermore, solar cells historically have been made from semiconductorssuch as silicon pn junctions. These junctions or diodes convert sunlightinto electrical power. These diodes can have a characteristically lowvoltage output, often on the order of 0.6 volts. Such cells may behavelike current sources in parallel with a forward diode. The outputcurrent from such a cell may be a function of many construction factorsand, is often directly proportional to the amount of sunlight.

The low voltage of such a solar cell can be difficult to convert topower suitable for supplying power to an electric power grid. Often,many diodes are connected in series on a photovoltaic panel. Forexample, a possible configuration could have 36 diodes or panelsconnected in series to make 21.6 volts. With the shunt diode andinterconnect losses in practice such panels might only generate 15 voltsat their maximum power point (MPP). For some larger systems having manysuch panels, even 15 volts may be too low to deliver over a wire withoutsubstantial losses. In addition, typical systems today may combine manypanels in series to provide voltages in the 100's of volts in order tominimize the conduction loss between the PV panels and a powerconverter.

Electrically, however, there can be challenges to finding the rightinput impedance for a converter to extract the maximum power from such astring of PV panels. The aspect of extracting power at a maximum powerpoint is often referred to as MPP tracking. Some such systems exist,however, there remain limitations, some of which are discussed here.First, the PV panels may act as current sources. As such, the panelproducing the lowest current may limit the current through the wholestring. In an undesirable case, if one weak panel is producingmoderately less, it might become back biased by the remainder of thepanels. Reverse diodes can be placed across each panel to limit thepower loss in this case and to protect the panel from reverse breakdown.

In systems, at least the following problems can arise and cause somedegree of loss in solar energy harvesting:

-   -   A. Non-uniformity between panels.    -   B. Partial shade    -   C. Dirt or accumulated matter blocking sunlight    -   D. Damage to a panel    -   E. Non-uniform degradation of panels over time

It may also be troublesome when expensive PV panels are placed in seriesand the weakest panel limits the power from every other panel.Unfortunately, the series connection may be desired to get high enoughvoltage to efficiently transmit power through a local distribution to aload, perhaps such as a grid-tied inverter. Further, in many systems,the PV panels may be located on a rooftop, such as for a residentialinstallation. And the inverter is often located at a distance from therooftop, such as by the power meter or the like. So in embodiments, away to connect the panels in series but not suffer the losses caused bythe lowest power panel, or any series parallel combination, may beneeded. There may also be a desire to use unlike types of panels at thesame time perhaps without regarding to the connection configurationdesired (series or parallel, etc.).

The techniques of photovoltaic power conversion have been recognized asan important limit to solar energy ultimately realizing its potential.Methods of solar power conversion have been proposed that utilize DC/DCconverters on each panel along with an MPP circuit as one attempt toenhance the efficiency of energy harvesting when utilizing strings ofsolar panels. Such attempts, however, have resulted in unacceptably lowefficiencies that have made such approaches impractical. Thesetechniques have even been dismissed to some degree by those consideringsuch issues. For example, in the article by G. R. Walker, J. Xue and P.Sernia entitled “PV String Per-Module Maximum Power Point EnablingConverters” those authors may have even suggested that efficiency losseswere inevitable but that this module approach held advantages, eventhough it was attended by poor efficiency. Similarly, two of the sameauthors, G. R. Walker and P. Sernia in the article entitled “CascadedDC-DC Converter Connection of Photovoltaic Modules” suggested that theneeded technologies are always at an efficiency disadvantage. Thesereferences even include an efficiency vs. power graph showing a fullpower efficiency of approximately 91%. With the high cost of PV panelsoperation through a low efficiency converter is simply not acceptable inthe marketplace.

Another less understood problem with large series strings of PV panelsmay be with highly varying output voltage, the inverter stage drivingthe grid my need to operate over a very wide range also lowering itsefficiency. It may also be a problem if during periods of time when theinverter section is not powering the grid that the input voltage to thisstage may increase above regulatory limits. Or conversely, if thevoltage during this time is not over a regulatory limit then the finaloperational voltage may be much lower than the ideal point of efficiencyfor the inverter.

In addition, there may be start-up and protection issues which addsignificant cost to the overall power conversion process. Other lessobvious issues affecting Balance of System (BOS) costs for a solar powerinstallation are also involved. Thus, what at least one aspect ofelectrical solar power needs is an improvement in efficiency in theconversion stage of the electrical system. The present inventionprovides this needed improvement.

DISCLOSURE OF THE INVENTION

As mentioned with respect to the field of invention, the inventionincludes a variety of aspects, which may be combined in different ways.The following descriptions are provided to list elements and describesome of the embodiments of the present invention. These elements arelisted with initial embodiments, however it should be understood thatthey may be combined in any manner and in any number to createadditional embodiments. The variously described examples and preferredembodiments should not be construed to limit the present invention toonly the explicitly described systems, techniques, and applications.Further, this description should be understood to support and encompassdescriptions and claims of all the various embodiments, systems,techniques, methods, devices, and applications with any number of thedisclosed elements, with each element alone, and also with any and allvarious permutations and combinations of all elements in this or anysubsequent application.

In various embodiments, the present invention discloses achievements,systems, and different initial exemplary architectures through which onemay achieve some of the goals of the present invention. Systems providealternating modes of photovoltaic conversion, high efficiency conversiondesigns, and even multimodal conversion techniques. Some architecturesmay combine a PV panel with MPP and even a dual mode power conversioncircuit to make what may be referred to as a Power Conditioner (PC)element. As discussed below, such Power Conditioners may be combined inseries or parallel or any combination of series/parallel and can bedesigned so that the solar panels will largely or even always producetheir full output. Even differing types of panels having differentoutput characteristics may be combined to produce maximum power fromeach panel. In some designs, a series string may be used to get a highvoltage useful for power transmission, and each Power Conditioner can bedesigned to make its maximum power.

In embodiments, this invention may permit each and every panel toindividually produce its maximum power thereby harvesting more totalenergy from the overall system. Systems may be configured with an MPPcircuit and a power conversion circuit on each panel. These circuits maybe made as simple inexpensive circuitry to perhaps perform severalfunctions. First, this circuit may be designed to extract the maximumpower available from each and every panel. Second, it may be configuredto transform to an impedance which naturally combines with the otherpanels in a series string. This circuit may also be configured forparallel connected panels or even for single cells or strings within apanel. Embodiments may be configured so that the output may be a highervoltage output (for example, 400V). Additionally, configurations mayallow for an easy to administer overvoltage or other protection, perhapseven with or without feedback elements that control the system to avoidan overvoltage or other condition.

The addition of individual MPP circuitry to a panel may even beconfigured so as to provide an inexpensive addition and, in someembodiments, may replace the need for the same function in the powerconverter. The circuitry may be added to the PV panels and may not needto be repeated in a grid-tied inverter. This may thus result in the sametotal circuitry with significant advantage. In embodiments there mayactually be several small MPP converters replacing one large one. Thismay result in even greater energy harvesting.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic of a conversion system according to oneembodiment of the invention for a single representative solar source.

FIG. 2 shows a schematic of a sea of interconnected strings of panelsaccording to one embodiment of the invention.

FIG. 3 shows a plot of a current and voltage relationship for arepresentative solar panel.

FIG. 4 shows a plot of a power and voltage relationship for a similarpanel.

FIGS. 5A and 5B show two types of dual mode power conversion circuitssuch as might be used in embodiments of the invention.

FIG. 6 shows an embodiment of the invention with series connected panelsand a single grid-tied inverter configuration.

FIGS. 7A and 7B show plots of solar panel output operational conditionsfor differing temperatures and output paradigms.

FIG. 8 shows a plot of losses by topology and range for traditionalapproach as compared to the present invention.

FIG. 9 shows a plot of combined protective and coordinated processconditions according to one operational embodiment of the invention.

FIG. 10 shows a prior art system with a grid-tied inverter.

MODE(S) FOR CARRYING OUT THE INVENTION

As mentioned above, the invention discloses a variety of aspects thatmay be considered independently or in combination with others. Initialunderstanding begins with the fact that one embodiment of a powerconditioner according to the present invention may combine any of thefollowing concepts and circuits including: an alternative processconverter, a dual mode photovoltaic converter, a very high efficiencyphotovoltaic converter, a multimodal photovoltaic converter, theinclusion of maximum power point tracking (MPP or MPPT) aspects into theforegoing, and even embodiments that include operational boundaries suchas for output voltage, output current, and perhaps even, output power.Each of these should be understood from a general sense as well asthrough embodiments that display initial applications forimplementation. Some initial benefits of each of these aspects arediscussed individually and in combination in the following discussion aswell as how each represents a class of topologies, rather than justthose initially disclosed.

FIG. 1 shows one embodiment of a solar energy power system illustratingthe basic solar conversion principles of the present invention. Asshown, it involves a solar energy source (1) feeding into a photovoltaicDC-DC power converter (4) providing a converted output to a photovoltaicDC-AC inverter (5) that may ultimately interface with a grid (10). Asmay be appreciated, the solar energy source (1) may be a solar cell, asolar panel, or perhaps even a string of panels. Regardless, the solarenergy source (1) may provide a DC photovoltaic output (2). This DCphotovoltaic output (2) may serve as a DC input (3) to the DC-DC powerconverter (4).

The DC-DC power converter (4) may have its operation controlled by acapability generally indicated as converter functionality controlcircuitry (8). As one of ordinary skill in the art should wellappreciate, this converter functionality control circuitry (8) may beembodied as true circuitry hardware or it may be firmware or evensoftware to accomplish the desired control and would still fall withinthe meaning of a converter functionality control circuitry (8).Similarly, the DC-DC power converter (4) should be considered torepresent photovoltaic DC-DC power conversion circuitry. In this regardit is likely that hardware circuitry is necessary, however combinationsof hardware, firmware, and software should still be understood asencompassed by the circuitry term.

As illustrated in FIG. 1, the various elements may be connected to eachother. Direct connection is but one manner in which the various elementsmay be responsive to each other, that is, some effect in one maydirectly or indirectly cause an effect or change in another. The DC-DCpower converter (4) may act to convert its input and thus provide aconverted DC photovoltaic output (6) which may serve as an input to theDC-AC inverter (5) which may be of a variety of designs. This DC-ACinverter (5) may or may not be included in embodiments of the solarenergy power system. If included, it may serve to accomplish the step ofinverting the DC power into an inverted AC (7) such as a photovoltaic ACpower output (7) that can be used by, for example, a power grid (10)through some connection termed an AC power grid interface (9). In thismanner the system may create a DC photovoltaic output (6) which may beestablished as an input to some type of DC-AC inverter (5). This step ofinverting an input should be understood as encompassing and creation ofany substantially alternating signal from any substantiallyunidirectional current flow signal even if that signal is not itselfperfectly, or even substantially, steady.

As shown in FIGS. 2 and 6, individual solar energy sources (1)—whetherat a cell, panel, or module level—may be combined to create a series ofelectrically connected sources. Such combinations may be responsivethrough either series or parallel connections. As shown in FIGS. 2 and6, the connected plurality may form a string of electrically connecteditems. Perhaps such as a string of electrically connected solar panels(11). As shown in FIG. 2, each of these strings may each themselves be acomponent to a much larger combination perhaps forming a photovoltaicarray (12) or even a sea of combined solar energy sources. By eitherphysical or electrical layout, certain of these cells, panels, orstrings may be adjacent in that they may be exposed to somewhat similarelectrical, mechanical, environmental, solar exposure (or insolative)conditions. In situations where large arrays are provided, it may bedesirable to include a high voltage DC-AC solar power inverter perhapswith a three phase high voltage inverted AC photovoltaic output asschematically illustrated in FIG. 2.

As illustrated for an electrically serial combination, output may becombined so that their voltages may add whereas their currents may beidentical. Conversely, electrically parallel combinations may exist.FIGS. 2 and 6 illustrate embodiments that are connected to accomplishserially combining or serially connecting items such as the converted DCphotovoltaic outputs (6) of each to create a converted DC photovoltaicinput to an DC-AC inverter (5). As shown, these serial connections maybe of the converted DC photovoltaic outputs (6) which may then create aconverted DC photovoltaic output (13) which may serve as a converted DCphotovoltaic input (14) to some type of photovoltaic DC-AC inverter (5)or other load. Again, each solar power source (1) may be at the cell,panel, string, or even array level. As would be well understood,parallel connections and the step of parallel connecting converters ortheir outputs could be accomplished as well.

As mentioned above, circuitry and systems can be configured to extractas much power as possible from the solar power sources (1).Electrically, this is accomplished by achieving operation to operate atone or more solar cell, panel, or string's maximum power point (MPP) byMPP circuitry or maximum power point tracking (MPPT). Thus, inembodiments, a solar power system according to the invention mayinclude: an MPPT control circuit with a power conversion circuit. It mayeven include range limiting circuitry as discussed later.

The aspect of maximum power point is illustrated by reference to FIGS. 3and 4 and the Maximum Power Point Tracking (MPPT) circuit may beconfigured to find the optimum point for extracting power from a givenpanel or other solar energy source (1). As background, it should beunderstood that a panel such as may be measured in a laboratory mayexhibit the voltage and current relationships indicated in FIG. 3.Current in Amps is on the vertical axis. Voltage in volts is on thehorizontal axis. If one multiplies the voltage times the current toderive power this is shown in FIG. 4. Power is now on the vertical axis.The goal of an embodiment of an MPPT circuit as used here may be toapply an appropriate load resistance or more precisely impedance to apanel such that the panel may operate to provide its peak power. One cansee graphically that the maximum power point on this panel under themeasurement conditions occurs when the panel produces approximately 15volts and 8 amperes. This may be determined by a maximum photovoltaicpower point converter functionality control circuitry (15) which mayeven be part or all of the modality of operation of the converterfunctionality control circuitry (8). In this fashion, the converter orthe step of converting may provide a maximum photovoltaic power pointmodality of photovoltaic DC-DC power conversion or the step of maximumphotovoltaic power point converting. As mentioned below, this may beaccomplished by switching and perhaps also by duty cycle switching andas such the system may accomplish maximum photovoltaic power point dutycycle switching or the step of maximum photovoltaic voltagedeterminatively duty cycle switching.

As one skilled in the art would appreciate, there are numerous circuitconfigurations that may be employed to derive MPP information. Some maybe based on observing short circuit current or open circuit voltage.Another class of solutions may be referred to as a Perturb and Observe(P&O) circuit. The P&O methods may be used in conjunction with atechnique referred to as a “hill climb” to derive the MPP. As explainedbelow, this MPP can be determined individually for each source, foradjacent sources, of for entire strings to achieve best operation. Thusa combined system embodiment may utilize individually panel (understoodto include any source level) dedicated maximum photovoltaic power pointconverter functionality control circuitries (16).

Regardless of whether individually configured or not, in one P&O method,an analog circuit could be configured to take advantage of existingripple voltage on the panel. Using simple analog circuitry it may bepossible to derive panel voltage and its first derivative (V′), as wellas panel power and its first derivative (P′). Using the two derivativesand simple logic it may be possible to adjust the load on the panel asfollows:

TABLE 1 V′ Positive P′ Positive Raise MPP V′ Positive P′ Negative LowerMPP V′ Negative P′ Positive Lower MPP V′ Negative P′ Negative Raise MPP

There may be numerous other circuit configurations for findingderivatives and logic for the output, of course. In general, a powerconditioner (17) may include power calculation circuitry (firmware, orsoftware)(21) which may even be photovoltaic multiplicative resultantcircuitry (22). These circuitries may act to effect a result or respondto an item which is analogous to (even if not the precise mathematicalresultant of a V*I multiplication function) a power indication. This mayof course be a V*I type of calculation of some power parameters and thesystem may react to either raise or lower itself in some way toultimately move closer to and eventually achieve operation at an MPPlevel. By provided a capability and achieving the step of calculating aphotovoltaic multiplicative power parameter, the system can respond tothat parameter for the desired result.

In embodiments where there is a series string of power conditioners (17)or the like, the current through each PC output may be the same but theoutput voltage of each PC may be proportional to the amount of power itspanel makes. Consider the following examples to further disclose thefunctioning of such embodiments. Examine the circuit of FIG. 6 andcompare it to panels simply connected in series (keep in mind that thesimple series connection may have a reverse diode across it). First,assume there are four panels in series each producing 100 volts and 1amp feeding an inverter with its input set to 400 volts. This gives 400watts output using either approach. Now consider the result of one panelmaking 100 volts and 0.8 amps (simulating partial shading—less lightsimply means less current). For the series connection the 0.8 amps flowsthrough each panel making the total power 400×0.8=320 watts. Nowconsider the circuit of FIG. 6. First, the total power would be 380watts as each panel is making its own MPP. And of course the currentfrom each Power Conditioner must be the same as they are after all stillconnected in series. But with known power from each PC the voltage maybe calculated as:

3V+0.8V=400 volts, where V is the voltage on each full power panel.

Thus, it can be seen that in this embodiment, three of the panels mayhave 105.3 volts and one may have 84.2 volts.

Further, in FIG. 6 it can be understood that in some embodiments, anadditional benefit may be derived from the inclusion of individual powercontrol. In such embodiments, a power block may be considered as a groupof PV panels with power conversion and MPP per panel configurations. Assuch they may adapt their output as needed to always maintain maximumpower from each and every power block. If adapted to be used with such astring of power blocks, the system may even operate with a varyingvoltage on its output.

The advantage of this type of a configuration is illustrated from asecond example of MPP operation. This example is one to illustrate whereone panel is shaded such that it can now only produce 0.5 amps. For theseries connected string, the three panels producing 1 amp may completelyreverse bias the panel making 0.5 amps causing the reverse diode toconduct. There may even be only power coming from three of the panelsand this may total 300 watts. Again for an embodiment circuit ofinvention, each PC may be producing MPP totaling 350 watts. The voltagecalculation would this time be:

3V+0.5V=400 volts

This, in this instance, the three panels may have a voltage of 114.2volts and the remaining one may have half as much, or 57.1 volts. Outputvoltage can be seen as proportional to PV panel output power thusyielding a better result.

These are basic examples to illustrate some advantages. In an actual PVstring today there may be many PV panels in series. And usually none ofthem make exactly the same power. Thus, many panels may become backbiased and most may even produce less than their individual MPP. Thiscan be overcome by embodiments of the present invention. In FIG. 6 thereis shown a power converter for taking power from this panel string andpowering the grid. As discussed below, such configuration may needvoltage limits and/or protection perhaps by setting operationalboundaries.

A power conditioner (17) may be configured to always extract the maximumpower from a PV panel. According to embodiments of the invention, thismay be accomplished by an impedance transformation capability providedthrough the power conditioner (17), the photovoltaic DC-DC powerconverter (4), or the converter functionality control circuitry (8).Such may act to transform the impedance of the individual or group powerdelivery as needed to maintain the MPP. The system may thus cause avariation in the voltage of each panel as it achieves maximum output foreach. Based on topology of the system, this may be accomplished perhapswith a constant or common current so the series string is at maximumpower. In embodiments, the invention may be configured to increase ordecrease the load impedance for one panel and may even provide a fixedvoltage if desired.

As suggested above, a photovoltaic impedance transformation modality ofphotovoltaic DC-DC power conversion can be accomplished by photovoltaicimpedance transformation power conversion control circuitry. Twoembodiments of switching or switchmode photovoltaic impedancetransformation photovoltaic DC-DC power converters are shown in FIGS. 5Aand 5B. As may be appreciated, the switches included may be controlledby converter functionality control circuitry (8) for duty cycleswitching, that is switching at periodic (even if not constant or ifhaving varying periods) times to accomplish a variety of goals. Thisswitching can occur in a variety of ways. There may also be variationsin the method for switching from one mode to another. For example, if aminimum pulse width is set, it may be possible to further reduce theenergy or alter the impedance by going to a burst mode as discussedbelow. If a minimum duty cycle is set to 2%, it is possible to get 0.2%energy transfer by using occasional bursts of the 2% duty cycle with aburst duty cycle of say 10%. Much of this may be achieved by frequencyaltered switching or other control of differing switches. Thusembodiment may provide switch frequency alteration switchingphotovoltaic power conversion control circuitry. This can give thepossibility of a smooth transformation from one mode to another whileproviding high efficiency during the transformation.

Goal in switching may include the maximum power point operationdiscussed above as well as a number of modalities as discussed below.Some of these modalities may even be slaved such that one takesprecedence of one or another at some point in time, in some powerregime, or perhaps based on some power parameter to achieve a variety ofmodalities of operation. Again some of these modalities are discussedlater. In the context of impedance transformation, however, there may bephotovoltaic impedance transformation duty cycle switching, and such maybe controlled by photovoltaic impedance transformation duty cycle switchcontrol circuitry (again understood as encompassing hardware, firmware,software, and even combinations of each).

With reference to the particular embodiments illustrated as but twoexamples in FIGS. 5A and 5B, it may be understood that the photovoltaicDC-DC power converter (4) may be operated to cause the photovoltaicimpedance to increase or decrease. These two alternative modes ofoperation may even be exclusive in that either one or the other mayexist at any point in time, even if such operations change over time. Assuch, embodiment may include photovoltaic impedance increasephotovoltaic DC-DC power conversion circuitry (19) and perhapsphotovoltaic impedance decrease photovoltaic DC-DC power conversioncircuitry (20). Examples of these two are illustrated in FIGS. 5A and 5Bwhere it can be considered that a first part of the photovoltaic DC-DCpower converter (4) acts in one way (up in FIG. 5A and down in FIG. 5B)and a second part of the photovoltaic DC-DC power converter (4) acts inthe other way (down in FIG. 5A and up in FIG. 5B). Thus it can be seenthat modes of operation in the photovoltaic DC-DC power converter (4)may be opposing in that one accomplishes an effect and the otheraccomplishes a contrary effect. Embodiments of the system may provide atleast one photovoltaic impedance increase modality of photovoltaic DC-DCpower conversion and at least one photovoltaic impedance decreasemodality of photovoltaic DC-DC power conversion. As shown for the twoembodiments in FIGS. 5A and 5B, both of these modalities may be providedin one photovoltaic DC-DC power converter (4) so that the photovoltaicDC-DC power converter (4) may achieve the steps of photovoltaic loadimpedance increasing and photovoltaic load impedance decreasing. Suchelements may also be disjunctive so that in alternative operation oneoperates when the other does not and visa versa. Such may also besubstantially disjunctive so that for only power conversioninsignificant periods where they both actually or appear to operate insimilar timeframes. Thus the system may include substantiallydisjunctive impedance transformation photovoltaic power conversioncontrol circuitry. Through the power conditioner (17) configuration anddesign the system may provide switching or other capability and, ifapplicable, control circuitry that may provide the desired effect.

Referring again to the embodiments shown in FIGS. 5A and 5B, it can beseen that some embodiments may utilize one or more switches that may becontrolled by photovoltaic switch control circuitry (23) and thus thepower conditioner (17) may be of a switchmode character. In theembodiments shown, these switches are designated T1-T4 and T21-T24. Insome embodiments, these switches may be semiconductor switches and thismay facilitate lower losses and higher efficiency. Furthermore, theswitches and connections may be configured to provide one or morephotovoltaic power series switch elements (24) and one or morephotovoltaic power shunt switch elements (25). As may be appreciated thephotovoltaic power series switch elements (24) may provide one or morelocations at which the transmission of photovoltaic power may beinterrupted (the act of interrupting) and the photovoltaic power shuntswitch elements (25) may provide one or more locations at which thetransmission of photovoltaic power may be shunted (the act of shunting)to ground, another power path, or the like.

As the illustrations in FIGS. 5A and 5B also illustrate, embodiments mayinclude not just one switch, not just one series and shunt switch, buteven pairs of series pathed and shunt pathed semiconductor (or other)switches. Thus, the interrupting and the shunting can occur at at leasttwo separate semiconductor switch locations. Obviously, these examplesare configured to more simply illustrate each of the switching,interrupting, shunting, and pairing concepts, however, it should beunderstood that more complex configurations are possible. As with manycircuitry aspects, some designs may even be arranged to elusivelyachieve the same effect; these would still fall within the scope of thepresent invention, of course.

As may be appreciated from just the initially discussed modes ofoperation, namely, the modes of increasing and, perhaps alternatively,decreasing photovoltaic load impedance, systems according to embodimentsof the present invention may provide a photovoltaic DC-DC powerconverter (4) that serves as a multimodal photovoltaic DC-DC powerconverter perhaps controlled by multimodal converter functionalitycontrol circuitry (26) in that it has more than one mode of operation.These modes may include, but should be understood as not limited to,photovoltaic impedance increasing and photovoltaic impedance decreasing;several other modes are discussed below. In general, the aspect ofmultimodal activity encompasses at least processes where only one modeof conversion occurs at any one time. Impedance, or any other factor, isnot increased and then decreased in the same process regardless of thedesired outcome. Only a single method of conversion is used, perhapswith a singular integration.

Thus, a power conditioner (17) may provide at least first modality andsecond modality photovoltaic DC-DC power conversion circuitry, DC-DCpower converter, or DC-DC power conversion. Further, as can beunderstood in an MPP context of increasing or decreasing photovoltaicload impedance, the multimodal photovoltaic DC-DC power converter orperhaps multimodal converter functionality control circuitry (26) mayrespond to one or more photovoltaic power condition, perhaps such as theV*I multiplicative factor, a voltage level, a current level, or someother perhaps signal indicated or calculated set point. In so offeringthe capability of more than one mode of conversion operation (eventhough not necessarily utilized at the same time), or in offering thecapability of changing modes of operation, the system may accomplish thestep of multimodally converting a DC photovoltaic input into a convertedphotovoltaic DC output. Similarly, by offering the capability ofcontrolling to effect more than one mode of conversion operation (again,even though not necessarily utilized at the same time), or incontrolling to change modes of operation, the system may accomplish thestep of multimodally controlling operation of a photovoltaic DC-DC powerconverter (4).

Embodiments may include even two or more modes of operation and thus maybe considered a dual mode power conversion circuit or dual modeconverter. The dual mode nature of this circuit may embody a significantbenefit and another distinction may be that most DC/DC converters areoften intended to take an unregulated source and produce a regulatedoutput. In this invention, the input to the DC/DC converter is regulatedto be at the PV panel MPP. The power taken from the PV panel may betransformed to whatever impedance is needed in the output connection tobe able to satisfy the input MPP requirement even without regarding tooutput.

In the case of the impedance being changed such that the output voltageis lower than the input voltage, T3 can be forced to be in a continuousconduction state and T4 in a non-conducting state with T1 and T2operated in a switchmode duty cycle state. This duty cycle of operationcan be synchronous in that the transistor T2 may be switchedsynchronously with T1 (with inverted duty cycle). T2 may be a lowR_(DS(ON)) FET having much lower losses than a diode in this location.By such synchronous operation this circuit can have extremely highefficiency as mentioned more generally below. A concern can exist forthis circuit in that current passes through an additional transistor,T3. But this transistor can have low loss as it is not switching.Similar operation can be achieved for the embodiment shown in FIG. 5B,of course.

A second mode for the circuit shown in FIG. 5A can involve the casewhere the impedance needs to be altered such that the output voltage ishigher than the input voltage. Now, T1 may be switched to a continuousconduction state. T2 may be non-conducting. Now transistors T3 and T4are controlled in a switchmode manner. One may see the same ideas apply.First, all switches are transistors having low on-state loss. Secondlythe boost section may operated with high efficiency with the onlyadditional loss due to the dual mode capability in the on-state loss oftransistor T1. This circuit can also make use of a common inductor L1saving size, space and cost. Again, as a person of ordinary skill in theart would understand, similar operation can be achieved for theembodiment shown in FIG. 5B.

Interesting, and as discussed in more detail below, while in prior artefficiency was sometimes shown to be less than 91%, this circuitaccomplishes the needed function while operating even above 98% and atlevels as high as 99.2% efficiency. When connected to a solar panel oran array of solar panels this efficiency difference can be of paramountimportance. Of course, isolated and non isolated impedancetransformations by analogy to DC/DC converters of many sorts may be usedwith other disclosed aspects of this invention, and almost any DC/DCconverter topology may be used for this function and is hereby includedin this invention

As mentioned briefly above, there may be alternating modes of operationand the system may vacillate (and achieve vacillatory conversion modes)between differing modes based upon a parameter or other indication orcalculation. In embodiments where one mode or another is substantiallyexclusively activated, a power conditioner (17) or other system elementmay provide an alternative mode photovoltaic power converterfunctionality control (27). It may exclusively switch between modes atat least some times. These modes may be modes of conversion and so thesystem may provide a vacillatory method of creating solar power. Asindicated above, these modes may be opposing or opposing modalities,substantially disjunctive, or otherwise.

In exclusively controlling a particular operational mode, systems maydisable an unused mode. This can be important, for example, to achievethe higher levels of efficiency mentioned below or the like. Referringto the examples illustrated in the context of photovoltaic impedancetransformation in FIGS. 5A and 5B, it can be understood how embodimentsof the invention can act to disable a mode of photovoltaic DC-DC powerconversion or operation at at least some times and thus the system canprovide disable alternative mode photovoltaic power conversion controlcircuitry (28). As discussed with respect to switch operation in thecontext of MPP, above, one or more switch(es), perhaps such as thephotovoltaic power shunt switch element (25), one of the photovoltaicpower series switch elements (24), or otherwise may be disabled duringan operation. This may provide a capability to compare modes ofoperation or, perhaps most importantly, may permit highly efficientoperation previously not believed achievable. Thus embodiments mayprovide photovoltaic disable mode converter functionality controlcircuitry.

An aspect of operational capability that afford advantage is thecapability of embodiments of the invention to accommodate differingoperating conditions for various solar sources or panels. As shown inFIGS. 7A and 7B, voltages of operation for maximum power point can varybased upon whether the solar source is experiencing hot or coldtemperature conditions. By permitting MPP to be accommodated throughimpedance transformation apart from any voltage constraint, embodimentsaccording to the invention may provide expansive panel capability. Thismay even be such that the converter is effectively a full photovoltaictemperature voltage operating range photovoltaic DC-DC power converterwhereby it can operate at MPP voltages as high as that for the MPP in acold temperature of operation as well as the MPP voltages as low as thatfor the MPP in a hot temperature of operation. Thus, as can beunderstood from FIGS. 7A and 7B, systems can provide solar energy sourceopen circuit cold voltage determinative switching photovoltaic powerconversion control circuitry and solar energy source maximum power pointhot voltage determinative switching photovoltaic power conversioncontrol circuitry. It can even achieve full photovoltaic temperaturevoltage operating range converting. This may be accomplished throughproper operation of the switch duty cycles and systems may thus providesolar energy source open circuit cold voltage determinatively duty cycleswitching and solar energy source maximum power point hot voltagedeterminatively duty cycle switching.

Further, viewing hot and cold voltages as perhaps the extremeconditions, similarly it can be understood how the system mayaccommodate varying amount of insolation and thus there may be providedinsolation variable adaptive photovoltaic converter control circuitrythat can extract MPP whether a panel is partially shaded, even ifrelative to an adjacent panel. Systems and their duty cycle switchingmay be adaptable to the amount of insolation and so the step ofconverting may be accomplished as insolation variably adaptivelyconverting. This can be significant in newer technology panels such ascadmium-telluride solar panels and especially when combining outputsfrom a string of cadmium-telluride solar panels which can have broaderoperating voltages.

As mentioned earlier, an aspect of significant important is the level ofefficiency with which the converter operates. This is defined as thepower going out after conversion over the power coming in beforeconversion. A portion of the efficiency gain is achieved by usingswitchmode operation of transistor switches, however, the topology isfar more significant in this regard. Specifically, by the operation ofswitches and the like as discussed above, the system can go far beyondthe levels of efficiency previously thought possible. It can evenprovide a substantially power isomorphic photovoltaic DC-DC powerconversion that does not substantially change the form of power intoheat rather than electrical energy by providing as high as about 99.2%efficiency. This can be provided by utilizing substantially powerisomorphic photovoltaic converter functionality and a substantiallypower isomorphic photovoltaic impedance converter and by controllingoperation of the switches so that there is limited loss as discussedabove. Such operation can be at levels of from 97, 97.5, 98, 98.5 up toeither 99.2 or essentially the wire transmission loss efficiency (whichcan be considered the highest possible).

One aspect that contributes to such efficiency is the fact that minimalamounts of energy are stored during the conversion process. As shown inFIGS. 5A and 5B, such embodiments may include a parallel capacitance anda series inductance. These may be used to store energy at at least sometimes in the operation of converting. It may even be considered thatfull energy conversion is not accomplished, only the amount ofconversion necessary to achieve the desired result. Thus embodiments mayserve as a low energy storage photovoltaic DC-DC power converter andeven a partial energy storage photovoltaic DC-DC power converter. Insituations where the voltage in and the voltage out are nearly identicaland thus the converter achieves unity conversion, there is evensubstantially no change in energy storage and so the system may haveembodiments that are considered a substantially constant energy storagephotovoltaic DC-DC power converter. Cycle-by-cycle energy storage mayalso be proportional (whether linearly, continuously, or not) to avoltage difference in conversion. Energy stored, perhaps in the inductormay also be proportional to a duty cycle for one or more switches. Partof the efficiency can also be considered as existing as a result of thefact that during operation some switches may remain static and eitheropen or closed. Thus embodiment may provide static switch alternativemode photovoltaic power conversion control circuitry and similarly,static switch converting. It may also provide fractional switch elementcontrol circuitry.

Switches can be controlled in a variable duty cycle mode of operationsuch that frequency of switching alters to achieve the desired facet.The converter functionality control circuitry (8) may thus serve asphotovoltaic duty cycle switch control circuitry. The duty cycleoperations and switching can achieve a variety of results, from servingas photovoltaic impedance transformation duty cycle switching, to otheroperations. Some of these may even be due to considerations apart fromthe conversion aspect that is the primary purpose of the photovoltaicDC-DC power converter (4).

While in theory or in normal operation the described circuits work fine,there can be additional requirements for a system to have practicalfunction. For example the dual mode circuit as described could go toinfinite output voltage if there were no load present. This situationcan actually occur frequently. Consider the situation in the morningwhen the sun first strikes a PV panel string with power conditioners(17). There may be no grid connection at this point and the invertersection may not draw any power. In this case the power conditioner (17)might in practical terms increase its output voltage until the inverterwould break. The inverter could have overvoltage protection on its inputadding additional power conversion components or, the power conditionermay simply have its own internal output voltage limit. For example ifeach power conditioner (17) could only produce 100 volts maximum andthere was a string of ten PCs in series the maximum output voltage wouldbe 1000 volts. This output voltage limit could make the grid-tiedinverter less complex or costly and is illustrated in FIG. 7A as apreset overvoltage limit. Thus embodiments can present maximum voltagedeterminative switching photovoltaic power conversion control circuitryand maximum photovoltaic voltage determinative duty cycle switching (asshown in FIG. 7A as the preset overvoltage limit). This can be inverterspecific.

A maximum output current limit may also be useful and is illustrated inFIG. 7A as the preset overcurrent limit. This is less straightforwardand is related to the nature of a PV panel. If a PV panel is subjectedto insufficient light its output voltage may drop but its output currentmay not be capable of increasing. There can be an advantage to onlyallowing a small margin of additional current. For example, this same100 watt panel which has a 100 volt maximum voltage limit could alsohave a 2 amp current limit without limiting its intended use. This mayalso greatly simplify the following grid tied inverter stage. Consideran inverter in a large installation which may need a crowbar shunt frontend for protection. If the output of a PC could go to 100 amps thecrowbar would have to handle impractical currents. This situation wouldnot exist in a non PC environment as a simple PV panel string could beeasily collapsed with a crowbar circuit. This current limit circuit mayonly be needed with a PC and it may be easily achieved by duty cycle ormore precisely switch operation control. Once a current limit isincluded another BOS savings may be realized. Now the wire size forinterconnect of the series string of PCs may be limited to only carrythat maximum current limit. Here embodiments can present maximumphotovoltaic inverter current converter functionality control circuitry,inverter maximum current determinative switching, photovoltaic invertermaximum current determinative duty cycle switch control circuitry, andphotovoltaic inverter maximum current determinatively duty cycleswitching or the like.

One more system problem may also be addressed. In solar installations itmay occur on rare conditions that a panel or field of panels may besubjected to more than full sun. This may happen when a refractorysituation exists with clouds or other reflective surfaces. It may bethat a PV source may generate as much as 1.5 times the rated power for afew minutes. The grid tied inverter section must either be able tooperate at this higher power (adding cost) or must somehow avoid thispower. A power limit in the PC may be the most effective way to solvethis problem. In general, protection of some other element can beachieved by the converter. This may even be a posterior or downstreamelement such as the inverter and so the converter functionality controlcircuitry (8) may serve to achieve photovoltaic inverter protectionmodality of photovoltaic DC-DC power conversion and may be considered asphotovoltaic inverter protection converter functionality controlcircuitry. Beyond protection, desirable inverter or other operatingconditions can be achieved by the converter, thus embodiments mayinclude photovoltaic inverter operating condition converterfunctionality control circuitry. These may be simply coordinated in somemanner such as by a photovoltaic inverter or posterior elementcoordinated modality or photovoltaic inverter or posterior elementcoordinated converter functionality control circuitry. There may also beembodiments that have small output voltage (even within an allowedoutput voltage range). This may accommodate an inverter with a smallenergy storage capacitor. The output voltage may even be coordinatedwith an inverter's energy storage capability.

As illustrated in FIGS. 7A, 7B, and 9, boundary conditions may be setsuch as the overcurrent limit and the overvoltage limit. Thus theconverter and/or its control circuitry may serve as photovoltaicboundary condition converter functionality control circuitry, mayachieve a photovoltaic boundary condition modality of photovoltaic DC-DCpower conversion, and may accomplish the step of controlling aphotovoltaic boundary condition of the photovoltaic DC-DC converter.

Yet another mode of operation may be to make a value proportional (inits broadest sense) to some other aspect. For example, there can beadvantages to making voltage proportional to current such as to providesoft start capability or the like. Thus embodiments may be configuredfor controlling a maximum photovoltaic output voltage proportional to aphotovoltaic output current at at least some times during the process ofconverting a DC input to a DC output. In general, this may provide softtransition photovoltaic power conversion control circuitry. And thesystem may include duty cycle control or switch operation that can beconducted so as to achieve one or more proportionalities between maximumvoltage output and current output or the like. Further, not only can anyof the above by combined with any other of the above, but each may beprovided in a slaved manner such that consideration of one modality issecondary to that of another modality.

A variety of results have been described above. These may be achieved bysimply altering the duty cycle of or switches affected by the switches.These can be accomplished based on thresholds and so provide thresholdtriggered alternative mode, threshold determinative, thresholdactivation, or threshold deactivation switching photovoltaic powerconversion control circuitry. A burst mode of operation perhaps such aswhen nearing a mode alteration level of operation may be provided and atsuch times frequency can be halved, opposing modes can be bothalternated, and level can be reduced as a change become incipient. Thiscan be transient as well. In these manners burst mode switchingphotovoltaic power conversion control circuitry and burst mode switchingcan be accomplished, as well as transient opposition mode photovoltaicduty cycle switch control circuitry and the step of transientlyestablishing opposing switching modes.

As mentioned above, the PCs and photovoltaic DC-DC power converters (4)may handle individual panels. They may be attached to a panel, to aframe, or separate. Embodiments may have converters physically integralto such panels in the sense that they are provided as one attached unitfor ultimate installation. This can be desirable such as when there areindependent operating conditions for separate solar sources, and evenadjacent solar sources to accommodate variations in insolation,condition, or otherwise. Each panel or the like may achieve its own MPP,and may coordinate protection with all others in a string or the like.

FIG. 10 illustrate one type of photovoltaic DC-AC inverter (5) that maybe used. Naturally as may be appreciated from the earlier commentsenhanced inverters that need not control MPP and that are alternativelyprotected by the converter may be used. Inverters may even have aseparate control input so that the input voltage is at a most optimallevel, perhaps such as a singular sweet spot or the like as illustratedby the bold vertical line in FIG. 9. Although other inventions by thepresent assignee address such aspects, they may be considered incidentalto the converter invention described here. Thus a more traditionalinverter is shown in FIG. 10. This may provide a connection to some typeof AC power grid interface (9).

As the invention becomes more accepted it may be advantageous to permitcomparison with more traditional technologies. This can be achieved bysimple switch operation whereby traditional modes of operation can beduplicated or perhaps adequately mimicked. Thus embodiments may includea solar power conversion comparator (29) that can compare first andsecond modes of operation, perhaps the improved mode of an embodiment ofthe present invention and a traditional, less efficient mode. Thiscomparator may involve indicating some solar energy parameter for each.In this regard, the shunt switch operation disable element may behelpful. From this a variety of difference can be indicated, perhaps:solar power output, solar power efficiency differences, solar power costdifferences, solar power insolation utilization comparisons, and thelike.

By the above combinations of these concepts and circuitry, at least someof the following benefits may be realized:

Every PV panel may produce its individual maximum power. Many estimatestoday indicate this may increase the power generated in a PVinstallation by 20% or even more.

-   -   The grid tied inverter may be greatly simplified and operate        more efficiently.    -   The Balance of System costs for a PV installation may be        reduced.

The circuitry, concepts and methods of various embodiments of theinvention may be broadly applied. It may be that one or more PCs perpanel may be used. For example there may be non-uniformities on a singlepanel or other reasons for harvesting power from even portions of apanel. It may be for example that small power converters may be used onpanel segments optimizing the power which may be extracted from a panel.This invention is explicitly stated to include sub panel applications.

This invention may be optimally applied to strings of panels. It may bemore economical for example to simply use a PC for each string of panelsin a larger installation. This could be particularly beneficial inparallel connected strings if one string was not able to produce muchpower into the voltage the remainder of the strings is producing. Inthis case one PC per string may increase the power harvested from alarge installation.

This invention is assumed to include many physical installation options.For example there may be a hard physical connection between the PC and apanel. There may be an interconnection box for strings in which a PC perstring may be installed. A given panel may have one or more PCsincorporated into the panel. A PC may also be a stand-alone physicalentity.

All of the foregoing is discussed in the context of a solar powerapplication. As may be appreciated, some if not all aspects may beapplied in other contexts as well. Thus, this disclosure should beunderstood as supporting other applications of the converter regardlesshow applied and even whether applied as a power converter, impedanceconverter, voltage converter, or otherwise.

As can be easily understood from the foregoing, the basic concepts ofthe present invention may be embodied in a variety of ways. It involvesboth solar power generation techniques as well as devices to accomplishthe appropriate power generation. In this application, the powergeneration techniques are disclosed as part of the results shown to beachieved by the various circuits and devices described and as stepswhich are inherent to utilization. They are simply the natural result ofutilizing the devices and circuits as intended and described. Inaddition, while some circuits are disclosed, it should be understoodthat these not only accomplish certain methods but also can be varied ina number of ways. Importantly, as to all of the foregoing, all of thesefacets should be understood to be encompassed by this disclosure.

The discussion included in this application is intended to serve as abasic description. The reader should be aware that the specificdiscussion may not explicitly describe all embodiments possible; manyalternatives are implicit. It also may not fully explain the genericnature of the invention and may not explicitly show how each feature orelement can actually be representative of a broader function or of agreat variety of alternative or equivalent elements. Again, these areimplicitly included in this disclosure. Where the invention is describedin device-oriented terminology, each element of the device implicitlyperforms a function. Apparatus claims may not only be included for thedevices and circuits described, but also method or process claims may beincluded to address the functions the invention and each elementperforms. Neither the description nor the terminology is intended tolimit the scope of the claims that will be included in any subsequentpatent application.

It should also be understood that a variety of changes may be madewithout departing from the essence of the invention. Such changes arealso implicitly included in the description. They still fall within thescope of this invention. A broad disclosure encompassing both theexplicit embodiment(s) shown, the great variety of implicit alternativeembodiments, and the broad methods or processes and the like areencompassed by this disclosure and may be relied upon when drafting theclaims for any subsequent patent application. It should be understoodthat such language changes and broader or more detailed claiming may beaccomplished at a later date. With this understanding, the reader shouldbe aware that this disclosure is to be understood to support anysubsequently filed patent application that may seek examination of asbroad a base of claims as deemed within the applicant's right and may bedesigned to yield a patent covering numerous aspects of the inventionboth independently and as an overall system.

Further, each of the various elements of the invention and claims mayalso be achieved in a variety of manners. Additionally, when used orimplied, an element is to be understood as encompassing individual aswell as plural structures that may or may not be physically connected.This disclosure should be understood to encompass each such variation,be it a variation of an embodiment of any apparatus embodiment, a methodor process embodiment, or even merely a variation of any element ofthese. Particularly, it should be understood that as the disclosurerelates to elements of the invention, the words for each element may beexpressed by equivalent apparatus terms or method terms—even if only thefunction or result is the same. Such equivalent, broader, or even moregeneric terms should be considered to be encompassed in the descriptionof each element or action. Such terms can be substituted where desiredto make explicit the implicitly broad coverage to which this inventionis entitled. As but one example, it should be understood that allactions may be expressed as a means for taking that action or as anelement which causes that action. Similarly, each physical elementdisclosed should be understood to encompass a disclosure of the actionwhich that physical element facilitates. Regarding this last aspect, asbut one example, the disclosure of a “converter” should be understood toencompass disclosure of the act of “converting”—whether explicitlydiscussed or not—and, conversely, were there effectively disclosure ofthe act of “converting”, such a disclosure should be understood toencompass disclosure of a “converter” and even a “means for converting”Such changes and alternative terms are to be understood to be explicitlyincluded in the description.

Any patents, publications, or other references mentioned in thisapplication for patent or its list of references are hereby incorporatedby reference. Any priority case(s) claimed at any time by this or anysubsequent application are hereby appended and hereby incorporated byreference. In addition, as to each term used it should be understoodthat unless its utilization in this application is inconsistent with abroadly supporting interpretation, common dictionary definitions shouldbe understood as incorporated for each term and all definitions,alternative terms, and synonyms such as contained in the Random HouseWebster's Unabridged Dictionary, second edition are hereby incorporatedby reference. Finally, all references listed in the List of Referencesother information statement filed with or included in the applicationare hereby appended and hereby incorporated by reference, however, as toeach of the above, to the extent that such information or statementsincorporated by reference might be considered inconsistent with thepatenting of this/these invention(s) such statements are expressly notto be considered as made by the applicant(s).

Thus, the applicant(s) should be understood to have support to claim andmake a statement of invention to at least: i) each of the power sourcedevices as herein disclosed and described, ii) the related methodsdisclosed and described, iii) similar, equivalent, and even implicitvariations of each of these devices and methods, iv) those alternativedesigns which accomplish each of the functions shown as are disclosedand described, v) those alternative designs and methods which accomplisheach of the functions shown as are implicit to accomplish that which isdisclosed and described, vi) each feature, component, and step shown asseparate and independent inventions, vii) the applications enhanced bythe various systems or components disclosed, viii) the resultingproducts produced by such systems or components, ix) each system,method, and element shown or described as now applied to any specificfield or devices mentioned, x) methods and apparatuses substantially asdescribed hereinbefore and with reference to any of the accompanyingexamples, xi) the various combinations and permutations of each of theelements disclosed, xii) each potentially dependent claim or concept asa dependency on each and every one of the independent claims or conceptspresented, and xiii) all inventions described herein. In addition and asto computerized aspects and each aspect amenable to programming or otherprogrammable electronic automation, the applicant(s) should beunderstood to have support to claim and make a statement of invention toat least: xiv) processes performed with the aid of or on a computer asdescribed throughout the above discussion, xv) a programmable apparatusas described throughout the above discussion, xvi) a computer readablememory encoded with data to direct a computer comprising means orelements which function as described throughout the above discussion,xvii) a computer configured as herein disclosed and described, xviii)individual or combined subroutines and programs as herein disclosed anddescribed, xix) the related methods disclosed and described, xx)similar, equivalent, and even implicit variations of each of thesesystems and methods, xxi) those alternative designs which accomplisheach of the functions shown as are disclosed and described, xxii) thosealternative designs and methods which accomplish each of the functionsshown as are implicit to accomplish that which is disclosed anddescribed, xxiii) each feature, component, and step shown as separateand independent inventions, and xxiv) the various combinations andpermutations of each of the above.

With regard to claims whether now or later presented for examination, itshould be understood that for practical reasons and so as to avoid greatexpansion of the examination burden, the applicant may at any timepresent only initial claims or perhaps only initial claims with onlyinitial dependencies. The office and any third persons interested inpotential scope of this or subsequent applications should understandthat broader claims may be presented at a later date in this case, in acase claiming the benefit of this case, or in any continuation in spiteof any preliminary amendments, other amendments, claim language, orarguments presented, thus throughout the pendency of any case there isno intention to disclaim or surrender any potential subject matter. Boththe examiner and any person otherwise interested in existing or laterpotential coverage, or considering if there has at any time been anypossibility of an indication of disclaimer or surrender of potentialcoverage, should be aware that in the absence of explicit statements, nosuch surrender or disclaimer is intended or should be considered asexisting in this or any subsequent application. Limitations such asarose in Hakim v. Cannon Avent Group, PLC, 479 F.3d 1313 (Fed. Cir2007), or the like are expressly not intended in this or any subsequentrelated matter.

In addition, support should be understood to exist to the degreerequired under new matter laws—including but not limited to EuropeanPatent Convention Article 123(2) and United States Patent Law 35 USC 132or other such laws—to permit the addition of any of the variousdependencies or other elements presented under one independent claim orconcept as dependencies or elements under any other independent claim orconcept. In drafting any claims at any time whether in this applicationor in any subsequent application, it should also be understood that theapplicant has intended to capture as full and broad a scope of coverageas legally available. To the extent that insubstantial substitutes aremade, to the extent that the applicant did not in fact draft any claimso as to literally encompass any particular embodiment, and to theextent otherwise applicable, the applicant should not be understood tohave in any way intended to or actually relinquished such coverage asthe applicant simply may not have been able to anticipate alleventualities; one skilled in the art, should not be reasonably expectedto have drafted a claim that would have literally encompassed suchalternative embodiments.

Further, if or when used, the use of the transitional phrase“comprising” is used to maintain the “open-end” claims herein, accordingto traditional claim interpretation. Thus, unless the context requiresotherwise, it should be understood that the term “comprise” orvariations such as “comprises” or “comprising”, are intended to implythe inclusion of a stated element or step or group of elements or stepsbut not the exclusion of any other element or step or group of elementsor steps. Such terms should be interpreted in their most expansive formso as to afford the applicant the broadest coverage legally permissible.

Finally, any claims set forth at any time are hereby incorporated byreference as part of this description of the invention, and theapplicant expressly reserves the right to use all of or a portion ofsuch incorporated content of such claims as additional description tosupport any of or all of the claims or any element or component thereof,and the applicant further expressly reserves the right to move anyportion of or all of the incorporated content of such claims or anyelement or component thereof from the description into the claims orvice-versa as necessary to define the matter for which protection issought by this application or by any subsequent continuation, division,or continuation-in-part application thereof, or to obtain any benefitof, reduction in fees pursuant to, or to comply with the patent laws,rules, or regulations of any country or treaty, and such contentincorporated by reference shall survive during the entire pendency ofthis application including any subsequent continuation, division, orcontinuation-in-part application thereof or any reissue or extensionthereon.

What is claimed is:
 1. An efficient solar energy power systemcomprising: a plurality of solar panels, each said solar panel having aDC photovoltaic output; a DC photovoltaic input that accepts power fromsaid DC photovoltaic output; at least one substantially power isomorphicphotovoltaic DC-DC power converter responsive to at least one said DCphotovoltaic input; substantially power isomorphic maximum photovoltaicpower point converter multimodal functionality control circuitry towhich said at least one substantially power isomorphic photovoltaicDC-DC power converter is responsive and that comprises up to about wiretransmission loss efficient photovoltaic conversion circuitry; aconverted photovoltaic DC power output connected to said at least onesubstantially power isomorphic photovoltaic DC-DC power converter; atleast one photovoltaic DC-AC inverter responsive to said photovoltaic DCpower output; and a photovoltaic AC power output responsive to said atleast one photovoltaic DC-AC inverter.
 2. An efficient solar energypower system as described in claim 1 wherein said plurality of solarpanels comprises a string of solar panels; and wherein saidsubstantially power isomorphic maximum photovoltaic power pointconverter multimodal functionality control circuitry comprises a paneldedicated substantially power isomorphic maximum photovoltaic powerpoint converter multimodal functionality control circuitry.
 3. Anefficient solar energy power system as described in claim 1 wherein saidsubstantially power isomorphic maximum photovoltaic power pointconverter multimodal functionality control circuitry to which said atleast one substantially power isomorphic photovoltaic DC-DC powerconverter is responsive comprises a substantially power isomorphicmaximum photovoltaic power point converter dual mode functionalitycontrol circuitry to which said at least one substantially powerisomorphic photovoltaic DC-DC power converter is responsive.
 4. Anefficient solar energy power system as described in claim 1 and furthercomprising photovoltaic boundary condition converter functionalitycontrol circuitry that achieves said boundary condition during operationof said system.
 5. An efficient solar energy power system as describedin claim 1 wherein said substantially power isomorphic maximumphotovoltaic power point converter multimodal functionality controlcircuitry is selected from a group consisting of: at least about 98%efficient photovoltaic conversion circuitry, at least about 98.5%efficient photovoltaic conversion circuitry, at least about 98% up toabout 99.2% efficient photovoltaic conversion circuitry, at least about98.5% up to about 99.2% efficient photovoltaic conversion circuitry, atleast about 98% up to about wire transmission loss efficientphotovoltaic conversion circuitry, and at least about 98.5% up to aboutwire transmission loss efficient photovoltaic conversion circuitry. 6.An efficient solar energy power system as described in claim 1 whereinsaid substantially power isomorphic maximum photovoltaic power pointconverter multimodal functionality control circuitry comprisessubstantially power isomorphic maximum photovoltaic power pointconverter multimodal functionality control circuitry selected from agroup consisting of: alternative mode photovoltaic power converterfunctionality control circuitry; photovoltaic impedance transformationpower conversion control circuitry; maximum photovoltaic power pointconverter functionality control circuitry; both photovoltaic loadimpedance increase converter functionality control circuitry andphotovoltaic load impedance decrease converter functionality controlcircuitry; multimodal converter functionality control circuitry;alternative mode photovoltaic power converter functionality controlcircuitry configured to alternatively switch at least some times betweenfirst modality photovoltaic DC-DC power conversion circuitry and secondmodality photovoltaic DC-DC power conversion circuitry; bothphotovoltaic load impedance increase converter functionality controlcircuitry and photovoltaic load impedance decrease converterfunctionality control circuitry; substantially power isomorphicphotovoltaic converter functionality control circuitry; photovoltaicduty cycle switch control circuitry; switch frequency alterationswitching photovoltaic power conversion control circuitry; transientopposition mode photovoltaic duty cycle switch control circuitry; firstmodality control circuitry; transient opposition mode control circuitry;and all permutations and combinations of each of the above.
 7. Anefficient solar energy power system as described in claim 1 wherein saidsubstantially power isomorphic maximum photovoltaic power pointconverter multimodal functionality control circuitry comprises maximumphotovoltaic inverter current converter functionality control circuitry.8. An efficient solar energy power system as described in claim 1wherein said substantially power isomorphic maximum photovoltaic powerpoint converter multimodal functionality control circuitry comprisesphotovoltaic inverter operating condition converter functionalitycontrol circuitry.
 9. An efficient solar energy power system asdescribed in claim 1 wherein said substantially power isomorphic maximumphotovoltaic power point converter multimodal functionality controlcircuitry comprises slaved maximum photovoltaic power point converterfunctionality control circuitry.
 10. An efficient solar energy powersystem as described in claim 1 wherein said substantially powerisomorphic maximum photovoltaic power point converter multimodalfunctionality control circuitry comprises slaved photovoltaic inverteroperating condition converter functionality control circuitry.
 11. Anefficient solar energy power system as described in claim 1 wherein saidsubstantially power isomorphic maximum photovoltaic power pointconverter multimodal functionality control circuitry comprises posteriorphotovoltaic element protection converter functionality controlcircuitry.
 12. An efficient solar energy power system as described inclaim 1 wherein said substantially power isomorphic maximum photovoltaicpower point converter multimodal functionality control circuitrycomprises photovoltaic inverter protection converter functionalitycontrol circuitry.
 13. An efficient solar energy power system asdescribed in claim 1 wherein said substantially power isomorphic maximumphotovoltaic power point converter multimodal functionality controlcircuitry comprises photovoltaic inverter coordinated converterfunctionality control circuitry.
 14. An efficient solar energy powersystem as described in claim 1 wherein said substantially powerisomorphic maximum photovoltaic power point converter multimodalfunctionality control circuitry comprises slaved photovoltaic voltageincrease and photovoltaic voltage decrease maximum photovoltaic powerpoint converter functionality control circuitry.
 15. An efficient solarenergy power system as described in claim 1 wherein said substantiallypower isomorphic maximum photovoltaic power point converter multimodalfunctionality control circuitry comprises maximum photovoltaic inverterinput voltage photovoltaic converter output voltage functionalitycontrol circuitry.
 16. An efficient solar energy power system asdescribed in claim 1 wherein said substantially power isomorphic maximumphotovoltaic power point converter multimodal functionality controlcircuitry comprises posterior photovoltaic operating condition converterfunctionality control circuitry.
 17. An efficient solar energy powersystem as described in claim 1 wherein said substantially powerisomorphic maximum photovoltaic power point converter multimodalfunctionality control circuitry comprises photovoltaic slaved modeconverter functionality control circuitry.
 18. An efficient solar energypower system as described in claim 1 wherein said substantially powerisomorphic maximum photovoltaic power point converter multimodalfunctionality control circuitry comprises photovoltaic inverter slavedconverter functionality control circuitry.
 19. An efficient solar energypower system as described in claim 1 wherein said substantially powerisomorphic maximum photovoltaic power point converter multimodalfunctionality control circuitry comprises threshold determinativeswitching photovoltaic power conversion control circuitry.
 20. Anefficient solar energy power system as described in claim 1 wherein saidsubstantially power isomorphic maximum photovoltaic power pointconverter multimodal functionality control circuitry comprises burstmode switching photovoltaic power conversion control circuitry.
 21. Anefficient solar energy power system as described in claim 1 wherein saidsubstantially power isomorphic maximum photovoltaic power pointconverter multimodal functionality control circuitry comprises burstmode control circuitry operated for occasional bursts of a particularduty cycle level for mode transition of said photovoltaic DC-DCconverter between a first modality of photovoltaic DC-DC powerconversion and a second modality of photovoltaic DC-DC power conversion.22. An efficient solar energy power system as described in claim 1wherein said at least one substantially power isomorphic photovoltaicDC-DC power converter comprises at least one multiple panel dedicatedsubstantially power isomorphic photovoltaic DC-DC power converter. 23.An efficient solar energy power system as described in claim 22 andfurther comprising an element selected from a group consisting of: astring of said plurality of solar panels connected to said at least onesubstantially power isomorphic photovoltaic DC-DC power converter,wherein said string of said plurality of solar panels is selected from agroup consisting of 10 solar panels, 8 solar panels, 4 solar panels, 3solar panels, and 2 solar panels.
 24. An efficient solar energy powersystem as described in claim 22 and further comprising at least oneseries string multiple panel dedicated substantially power isomorphicphotovoltaic DC-DC power converter.
 25. An efficient solar energy powersystem comprising: a plurality of solar panels, each said solar panelhaving a DC photovoltaic output; a DC photovoltaic input that acceptspower from said DC photovoltaic output; first modality photovoltaicDC-DC power conversion circuitry responsive to said DC photovoltaicinput; second modality photovoltaic DC-DC power conversion circuitryresponsive to said DC photovoltaic input; at least one photovoltaicDC-DC power converter responsive to at least one said DC photovoltaicinput; high efficiency multimodal converter functionality controlcircuitry to which said at least one photovoltaic DC-DC power converteris responsive and wherein said high efficiency multimodal converterfunctionality control circuitry is configured to switch at least sometimes between said first modality photovoltaic DC-DC power conversioncircuitry and said second modality photovoltaic DC-DC power conversioncircuitry, and configured to achieve up to about wire loss transmissionefficiency; a converted photovoltaic DC power output connected to saidat least one photovoltaic DC-DC power converter; at least onephotovoltaic DC-AC inverter responsive to said photovoltaic DC poweroutput; and a photovoltaic AC power output responsive to said at leastone photovoltaic DC-AC inverter.
 26. An efficient solar energy powersystem as described in claim 25 wherein said substantially powerisomorphic photovoltaic converter functionality control circuitry isselected from a group consisting of: at least about 98% efficientphotovoltaic conversion circuitry, at least about 98.5% efficientphotovoltaic conversion circuitry, at least about 98% up to about 99.2%efficient photovoltaic conversion circuitry, at least about 98.5% up toabout 99.2% efficient photovoltaic conversion circuitry, at least about98% up to about wire transmission loss efficient photovoltaic conversioncircuitry, and at least about 98.5% up to about wire transmission lossefficient photovoltaic conversion circuitry.
 27. An efficient solarenergy power system comprising: at least one string of a plurality ofsolar panels, at least one of said solar panels having a DC photovoltaicoutput; a DC photovoltaic input that accepts power from said string of aplurality of solar panels having said DC photovoltaic output; at leastone multiple panel dedicated substantially power maximum photovoltaicpower point DC-DC power converter responsive to at least one said DCphotovoltaic input from said string of a plurality of solar panels;converter multimodal functionality control circuitry to which said atleast one multiple panel dedicated substantially power maximumphotovoltaic power point DC-DC power converter is responsive; aconverted photovoltaic DC power output connected to said at least onemultiple panel dedicated substantially power maximum photovoltaic powerpoint DC-DC power converter; at least one photovoltaic DC-AC inverterresponsive to said converted photovoltaic DC power output; and aphotovoltaic AC power output responsive to said at least onephotovoltaic DC-AC inverter.
 28. An efficient solar energy power systemas described in claim 27 wherein said converter functionality controlcircuitry comprises converter functionality control circuitry selectedfrom a group consisting of: alternative mode photovoltaic powerconverter functionality control circuitry; photovoltaic impedancetransformation power conversion control circuitry; maximum photovoltaicpower point converter functionality control circuitry; both photovoltaicload impedance increase converter functionality control circuitry andphotovoltaic load impedance decrease converter functionality controlcircuitry; both photovoltaic load impedance increase converterfunctionality control circuitry and photovoltaic load impedance decreaseconverter functionality control circuitry; multimodal converterfunctionality control circuitry; alternative mode photovoltaic powerconverter functionality control circuitry configured to alternativelyswitch at least some times between first modality photovoltaic DC-DCpower conversion circuitry and second modality photovoltaic DC-DC powerconversion circuitry; substantially power isomorphic photovoltaicconverter functionality control circuitry; photovoltaic duty cycleswitch control circuitry; switch frequency alteration switchingphotovoltaic power conversion control circuitry; transient oppositionmode photovoltaic duty cycle switch control circuitry; first modalitycontrol circuitry; transient opposition mode control circuitry;photovoltaic disable mode converter functionality control circuitry; andall permutations and combinations of each of the above.
 29. An efficientsolar energy power system as described in claim 27 wherein saidconverter functionality control circuitry comprises converterfunctionality control circuitry selected from a group consisting of:burst mode switching photovoltaic power conversion control circuitry;burst mode control circuitry operated for occasional bursts of aparticular duty cycle level for mode transition of said photovoltaicDC-DC converter between a first modality of photovoltaic DC-DC powerconversion and a second modality of photovoltaic DC-DC power conversion;slaved photovoltaic voltage increase and photovoltaic voltage decreasemaximum photovoltaic power point converter functionality controlcircuitry; slaved maximum photovoltaic power point converterfunctionality control circuitry; slaved photovoltaic inverter operatingcondition converter functionality control circuitry; slaved photovoltaicload impedance increase converter functionality control circuitry;slaved photovoltaic load impedance decrease converter functionalitycontrol circuitry; both slaved photovoltaic load impedance increaseconverter functionality control circuitry and slaved photovoltaic loadimpedance decrease converter functionality control circuitry;photovoltaic slaved mode converter functionality control circuitry; allpermutations and combinations of each of the above.
 30. An efficientsolar energy power system as described in claim 27 wherein saidconverter functionality control circuitry comprises converterfunctionality control circuitry selected from a group consisting of:photovoltaic boundary condition converter functionality controlcircuitry; maximum photovoltaic inverter current converter functionalitycontrol circuitry; maximum photovoltaic inverter input voltagephotovoltaic converter output voltage functionality control circuitry;posterior photovoltaic element protection converter functionalitycontrol circuitry; photovoltaic inverter protection converterfunctionality control circuitry; photovoltaic inverter coordinatedconverter functionality control circuitry; posterior photovoltaicoperating condition converter functionality control circuitry; posteriorphotovoltaic element protection converter functionality controlcircuitry; photovoltaic inverter protection converter functionalitycontrol circuitry; photovoltaic inverter coordinated converterfunctionality control circuitry; photovoltaic inverter slaved converterfunctionality control circuitry; and all permutations and combinationsof each of the above.
 31. An efficient solar energy power system asdescribed in claim 27 and further comprising a string of said pluralityof solar panels connected to said at least one multiple panel dedicatedsubstantially power maximum photovoltaic power point DC-DC powerconverter, wherein said string of said plurality of solar panels isselected from a group consisting of 10 solar panels, 8 solar panels, 4solar panels, 3 solar panels, and 2 solar panels.
 32. An efficient solarenergy power system as described in claim 27 wherein said convertermultimodal functionality control circuitry comprises photovoltaicboundary condition converter functionality control circuitry;
 33. Anefficient solar energy power system as described in claim 27 whereinsaid converter multimodal functionality control circuitry comprisesmaximum photovoltaic inverter current converter functionality controlcircuitry.
 34. An efficient solar energy power system as described inclaim 27 wherein said converter multimodal functionality controlcircuitry comprises photovoltaic inverter operating condition converterfunctionality control circuitry.
 35. An efficient solar energy powersystem as described in claim 27 wherein said converter multimodalfunctionality control circuitry comprises slaved photovoltaic voltageincrease and photovoltaic voltage decrease maximum photovoltaic powerpoint converter functionality control circuitry.
 36. An efficient solarenergy power system as described in claim 27 wherein said convertermultimodal functionality control circuitry comprises maximumphotovoltaic inverter input voltage photovoltaic converter outputvoltage functionality control circuitry.